Soft-face attachment for pneumatic hammers



May 21, 1946. q LEFEBVREF' 1 2,400,333

SOFT-FACE ATTACHMENT FOR PNEUMATIC HAMMERS Filed Feb. 9, 1944 Inventor Z514; d'dl' afeiw Attoineyo' Patented May 21, 1946 SOFT-FACE ATTACHMENT FOR PNEUMATIC HAMMERS Lodas Charles Lei'ebvre, Ville Ste-Laurent, near Montreal, Quebec, Canada Application February 9, 1944, Serial No. 521,702

1 Claim.

The present invention relates to a soft-face hammer and, more particularly, such a hammer attachable to pneumatic or the like percussion devices. 7

Of course, hand mallets or hammers having a soft-face are known and are used for a variety of purposesrtheir utility for specific functions, such as hammering out dents in aluminum and other soft-metal flat sheets is recognized to the extent that, most of this flattening work is still done by hand for want of better means.

Attempts to use pneumatic riveters and guns, with a soft face, have failed due to mechanical considerations connected with the guns themselves, and the tremendous pounding and vibration caused by said pneumatic means.

The present invention has been conceived to provide an attachment for pneumatic riveters which renders feasible and practical the use of a soft face on such pneumatic devices.

The main object of the invention, therefore, resides in the provision of means adaptable to a pneumatic riveter to transform said riveter into an efiicient, practical and quickly removable softface hammer. i

Another important object is the provision of an attachment of the character described, which is simple, rugged and adapted to resist the destructive effects of the percussion hammers.

Still another object contemplates a pneumatic riveter attachment having means for removably holding a plug of raw-hide or the like which serves as a soft-face hammer.

A further object is the provision of a soft-face hammer attachment, which can be quickly connected to any pneumatic hand riveter without changes thereto.

A still further object concerns an attachment of the type described, which can be manufactured easily at relatively low cost.

Other objects and advantages of the invention will become apparent, or be further pointed out, during the description to follow.

As an example, and for purposes of illustration only, a preferred embodiment of the invention is shown in the annexed drawing wherein? Figure 1 is an elevational view of the invention attached to the end of a hand riveter,

Figure 2 is a sectional view taken on the line 22 of Figure 1,

Figure 3 is a vertical section taken on the line 33 of Figure 2, and

Figure 4 is also a vertical section, but taken at right angle to the line 33 of Figure 2.

Referring to the drawing, wherein similar reference' characters represent corresponding parts throughout, the letter R generally indicates the end or tip of a hand riveter, said-riveter having usually an internally movable pistonand adapted to receive a tool pressed against said piston by a spiral spring. S. This spring is generally threaded into screw-threads T formed on the outer face of the riveter tip, said spring having its outer bottom coil D of diminishing diameter to provide a neck engaging a shoulder A formed on the tool B intermediate its length. After winding the spring upwardly until the tool B is tightly pressed against the inner piston of the riveter (not shown), it may be secured in place by means of a pin P. Obviously, the purpose of such an arrangement is to resiliently press the tool against the reciprocating inner piston of the riveter, to prevent the falling out of said tool.

The soft-face attachment of the invention is adapted to be used in connection with the riveter through the intermediary of a shaft replacing, naturally, the tool B, such as a chisel, pointer or swager. 'This shaft corresponding, therefore, to the tool B, also has a shoulder A but, the lower end thereof below said shoulder is tapered downwardly to form an attachment receiving stub 5, said stub being apertured transversely slightly below its middle point to receive a pin 6, the purpose of which will be described later on.

The attachment proper consists of a body, generally indicated at 1, comprising a lower bottom section, 8 and an upper conically shaped, tapering section 9. The lower section is bored concentrically with the outer surface thereof, so that only a relatively thin wall remains, the inner surface of said wall converging slightly from the inside to the outside, so that any plug inserted therein may be removed with more facility, when desired, than with strictly parallel walls. This inside bore of the section 8, consequently, forms a cavity l0 into which a plug of suitable material is adapted to be inserted, said plug constituting the soft-face of the hammer. Preferably, it is intended to use an involutely coiled strip ll, of raw hide, closely wound upon itself and forced into the cavity 9 so as to extend therefrom a short distance only; obviously, other materials can be used also, such as lead, various plastics, fibre and even certain types of leather as well as wood and the like.

As shown to advantage in Figures 3 and 4, the upper conical section 9 has a central longitudinal bore l3 tapered to correspond to the stub 5 and adapted to receive the same; it is to be noted that the bottom of the cavity I3 terminates a short distance above the cavity l0, so that a part of the thrust received by the attachment from the shaft stub is distributed to the bottom of the cavity 13, as well as on the sides thereof. The section 9 is furthermore provided with another transverse bore [4, formed at right angles to the bore l3, the purpose of said bore It being to accommodate the pin 6 which, as previously disclosed, is inserted across the stub 5 and consequently projects outwardly therefrom. As shown in Figure 3, the bore I4 is slightly wider than the diameter of the pin 6 and, furthermore, elongated in a vertical plane so that it is of oval crosssection; this peculiar shape of the bore I4 is to accommodate the motion of the pin 6 which, following the movement of the stub 5, may, under special circumstances, vibrate within the section 9 and must have the necessary space for this vibration if striking of the pin against the side of the bore. [4 is. tobe prevented.

The body 118. normally held to the stub 5. by means of pairs of springs l5; the inner end of one pair of springs being connected to each end of the pin 6 in grooves, l8. formed at the extreme end of said pin, as shown in Figure 3. The outer ends. of the springs are in turn connected to a triangular plate I! having apertures H3 at the upper corners to receive the said springs. The lower end of said plate II has a hole through which a threaded bolt I9 is adapted to extend, said bolt retaining the plate H in place, one on each side of the body, by means of a head 2,0. and a nut 2|. As shown to advantage in Fig. 4, the bolt is extends. through the plug D constituting the soft-face hammer .and, consequently, is adapted to retain the same in the cavity It] against the bottom of said cavity due to the action of the springs IE on the plates 51, which in turn are secured to the bolt :9.

, For the same reason as. in the case of pin 6, the bolt l9 traverses the wall of section 8 through an enlarged aperture 25, whereby the end of said bolt l29- may have space. to vibrate freely should the plug Dbecome loose in its. cavity. This might 45 occur after long periods of rest, during which time the plug D. may have time to dry and shrink slightly; due to the action of the strong spring S and the inertia of the hammer attachment, it is possible that the stub shaft 5 may be withdrawn from its cavity when the hammer is not pressed against a solid surface. Therefore, the purpose of the spring I5 is to prevent the complete removal of the stub from the attachment, and to, retain said attachment thereof; the same action may occur in the caseof the plug and, therefore, the bolts 19 securely'held by said plug will permit the falling out of the plug. In other words, all units are tied together through the intermediary of the spring I5 and held together in a resilient manner.

From the foregoing it will be evident that the present invention is an advance of the art in percussion hammers, in that it provides the means for attachin the top-face hammer to a pneumatic or other mechanical riveter, said means being conceived that no chain is necessary or required in the. riveter, said means being furthermore designed to sustain the vibration and pounding imparted thereto, so as to operate efficiently and easily for very long periods of time.

It must be understood that various changes as to size, arrangement andshape of parts may be resorted to. without. departing from the spirit of the invention or the scope of the subjoined claim.

Having thus described my invention, I claim:

A tool of the characterdescribed, comprising a hammer body havingv a lower cavity, a soft plug in said cavity; an upper tapered bore and apertures disposed at the top and bottom thereof and openings respectively in the upper bore and lower cavity in right angularly disposed pairs, a shaft having a tapered section to fit in the tapered bore, said shaft having an aperture disposedtransversely in the tapered section, an upper pin in the shaft aperture extending out of the body through the upper apertures thereof, a second pin inserted in the lower apertures of the body a-nd through the soft plug therein, and pairs of springs secured at Onepnd to the ends of the second pin and joined at their other end to the ends of the upper pin.

LODAS CHARLES LEFEBVRE. 

